The letter written by Johannes Marcus Marci to Athanasius Kircher in 1665—often referred to as the Marci Letter—has been a cornerstone element in the putative provenance of the Voynich Manuscript. The letter, traditionally treated as a separate document found within the front cover of the manuscript, raises a number of unresolved questions regarding its physical characteristics and its relationship to the codex. This study reinterprets the evidence to argue that the Marci Letter was not a loosely associated cover letter but was instead conceived, written, and sent by Marci as a tipped-in component of the manuscript itself, functioning as a flyleaf within the codex. The hypothesis requires minimal speculation and offers a plausible, evidence-based model consistent with observed facts. It is presented as a testable codicological hypothesis—not a definitive theory—aimed at resolving several of the manuscript’s physical and historical anomalies. It makes no attempt to overturn the established historical framework, but seeks to clarify and unify it.